1. Field of the Invention
The present invention relates to a plug, in particular to a safety plug with positioned components thereof.
2. Description of the Related Art
Unless otherwise indicated herein, the elements described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
The electricity is now everywhere around our living life, such as a television, a refrigerator, a computer and so on. With depending more and more closely on the electricity, the safety toward the plug becomes more and more important.
As discloses in R.O.C. Pat. No.268666, as shown in the FIG. 1A, a plug 1 includes a housing 111 and a cover (non shown). Between the housing 111 and the cover are two metal blade 112  113. One electrode 125a of the wire 125 reaches the housing 11a and contacts with the metal blade 113. One extremity of the other metal blade 112 forms a contact sheet 1126 where in a bimetallic strip 114 is fastened onto the contact sheet 1126. One extremity of the bimetallic strip 114 forms a contactor 1142 and beneath the contactor 1142 is a contact part 1162 of a conducting device 116 which fixed onto the housing 111. One extremity of the conducting device 116 is a hole 1164 ,using for contacting with another electrode 125b of the wire 125. A shaft 120 is disposed beneath the bimetallic strip 114 and the shaft 120 is made from isolated material. A isolating sheet 122 extrudes from the shaft 12. A spring 124 leans against the inner wall of the housing 111 and at the side of the isolating sheer 122. Thus, after the plug 1 is overloaded with electrical appliances, the contactor 1142 jumps. Based on the elasticity of the spring 124, the isolating sheet 122 would between the contractor 1142 of the isolating sheet 122 and the contractor 1162 of the conducting device 116. The plug cuts off the power supply then. To recover the electrified needs to press the shaft 120 down that causes the isolating sheet 122 removed from the between the bimetallic strip 114 and the conducting device 116. When the temperature descends, the contactor 1142 of the bimetallic strip 114 goes back to the same place where connects with the contractor 1142 of the bimetallic strip 114 and the contractor 1162 of the conducting device 116. Then, the plug returns to on working form.
However, the aforementioned conventional plug doesn't have any structure for fastening the shaft 120  bimetallic strip 114 and the conducting device 116. Also, the bimetallic strip 114 fasten on the contact sheet 1126 only by a rivet 1144. In this way results in many disadvantages:
First, the bimetallic strip 1126 is used to convert a temperature change in this case. It consists of two strips of different metals which have different thermal expansion and expand at different rates as they are heated. The bimetallic strip 1125 bends when heated. Thus, the sensitive requirement must be exact. The aforementioned conventional plug uses only a rivet to fasten the metal strip on the contact sheet 1126 without any connection on the housing thus easily causes the metal strip shifted after the temperature variation. The plug is not stable enough in this arrangement, so as the reliability.
Second, as shown in the FIG. 1B, the wire 125 reaches the housing 111 and make a contact with the metal blade 113 and the conducting device 116. However, the electrodes 125a and 125b of the wire 125 whirled around some components affects the bimetallic strip sometimes, especially when the wire 125 is pulled.